This invention relates generally to circuits for storing electrical analog signals and particularly to one which includes means for incrementally changing the value of a stored signal.
Under certain circumstances it may be desirable to store an analog signal before it is further processed. E.g. analog signals representative of the conditions at various steps of a manufacturing process are received by data processing equipment for subsequent interpretation and manipulation to determine whether the process is operating within specification or without. These signals cannot, necessarily, be processed at the actual time of their occurrence. Data is received from the various monitoring points to be evaluated well after the instant at which it occurs.
Further, certain analog signals will represent monitored conditions such as the temperature at a particular step in a control process while other analog signals are generated as control signals to alter operating conditions within a process as reflected by the monitored signals. These latter control signals must be changeable, oftentimes by fine, precise increments, to effect necessary changes in particular operating conditions.
It is therefore a primary object of this invention to provide a circuit which can store an analog signal as long as need be prior to further processing.
It is still another object of this invention to provide a circuit which will allow for incremental changes to be made to the stored signal.